Photochromic compounds (7)

ABSTRACT

Disclosed are photochromic oxazine compounds, yielded by means of condensation of an aldehyde bearing in the α-position to the aldehyde group a halogen or hydroxy group (reacting agent 1), with (substituted) ortho-aminohydroxy aromatic compounds (reacting agent 2).

DESCRIPTION

This application is a 371 of PCT/DE94/00744, filed Jun. 28, 1994.

1. Technical Field

The present invention relates to photochromic compounds, in particular,for the tinting of optical elements made of plastic material.

2. State of the Art

Pyrans are a class of photochromic compounds that have been known forsome time and have been extensively investigated. For instance, recentlydeveloped photochromic dyes such as the diphenyl-naphthopyrans describedin U.S. Pat. No. 5,066,818, the PCT publication WO 92/09593 or U.S. Pat.No. 4,818,096 have within wide bounds adjustable kinetic properties.Their lifetime, i.e. their light stability in continuous use is howeverinsufficient for many applications.

Spiropyrans, which are spiro-linked in the 2-position also showinsufficient light stability. This is also the case with the adamantanderivatives described in the U.S. Pat. No. 4,818,096 as well as with thederivatives described in U.S. Pat. No. 5,106,998 principally tricyclichydrocarbons.

The compounds of the class of indolino-(spirobenz- or naphthoxazines)hitherto preferred for their excellent stability such as those , e.g.,described in U.S. Pat. No. 3,652,172, U.S. Pat. No. 3,578,602, U.S. Pat.No. 4,215,010 or U.S. Pat. No. 4,637,698 can be minimally influencedwith regard to their darkening and lighting speed.

DESCRIPTION OF THE INVENTION

The object of the present invention is to describe photochromiccompounds and to provide a mode of synthesis of these compounds havingthe advantageous properties of pyrans and, in particular ofdiphenylnaphthopyrans with a lifetime respectively a light stabilitycomparable to that of oxazines known, in particular, fromindolinospironaphtho or indolinospirobenz derivatives.

According to the present invention, the object is solved by thecondensation of substituted diphenylacetaldehydes (reacting agent 1)with (substituted) ortho-aminohydroxy aromatic compounds (reacting agent2). This yields a new class of substances having the needed positiveproperties. Especially preferred is a halogen or hydroxy group which islocated in the α-position to the aldehyde group and condenses with thehydroxy group of the reacting agent 2 releasing water or halogenhydrogen. One or both phenyl residues may, of course, also be furthersubstituted.

The reaction can also be conducted with (substituted) dinaphthylderivatives or phenylnaphthyl derivatives as reacting agent 1;heteroaromatic compounds may also be employed.

Both phenyl rings of reacting agent 1 may also be chemically rigidlylinked (e.g., fluorene, dibenzosuberone, anthrone, xanthene orthioxanthene derivatives) as was described in an application filed onthe same day of the same applicant.

The kinetic properties of the invented compounds may be influenced in ananalogous manner to the method according to WO 92/09593 in particularvia subtituents in the 2-position of the aromatic rings of reactingagent 1.

The second reacting agent especially preferably possesses anortho-amino-hydroxy group at an aromatic ring system. This may beanother substituted benzene, naphthalene, phenanthrene, anthracene or,by way of illustration, quinoline respectively isoquinoline from theseries of heteroaromatic compounds.

Preferred are 1-amino-2-naphtholes, with the kinetic properties beingeasily influenced by means of suited substitution in the 3-positionanalog to U.S. Pat. No. 5,066,818.

The condensation itself can be conducted with the free base, thehydrochloride or with modification of the specifications also with byway of illustration amino groups protected by an acetyl group.

Suited as solvents are, in particular, such solvents that form withwater a low-boiling azeotrope so that the reaction water can be easilyremoved, by way of illustration, by means of a Dean-Stark apparatus. Thehydrohalogen is extracted or bound, by way of illustration, in anextractor by a stable alkali hydroxide. Depending on the utilizedreacting agents, the reaction is preferably catalyzed with a base or anacid (p-toluol-sulfonic acid).

DESCRIPTION OF PREFERRED EMBODIMENTS Mode of Synthesis

In the following, a synthesis is described based on 1-amino-2-naphthol.All the compounds of table 1 were synthesized in an analogous manner.The corresponding nitroso derivatives can also obtained by reducing thenitro derivatives (cf. Liebermann and Jacobson, Ann. 211, 48 (1882)).This mode is disadvantageous because of the predominantly yielded4-nitro-1-naphthols in the preliminary stage for the compounds 1-3. Theanalog hydroxy compounds can principally be utilized instead of thehalogen acetaldehyde compounds, the yields however are, i.a., distinctlyless.

The methyl substituted diphenyl-acetaldehydes respectivelynaphthylphenyl-acetaldehydes required for compounds 3, 7 and 9 can berepresented according to specifications in the literature.

1. Bromification of diphenylacetaldehyde

25 g (0.13 mol) of diphenylacetaldehyde are dissolved with nitrogenscavenging in 100 ml of carbon tetrachloride released of oxygen. Thesolution is cooled to -5° C. and slowly dripped to 21 g (0.26 mol) ofbromine. The temperature should never exceed -3° C. The solution turnsbrown with the intially rapid bromine tinting distinctly slowing downwith time. While heating to about 5° C. the untransformed bromine isextracted with nitrogen until a honey-yellow solution is left. Afterwithdrawl of the CC14, 30.8 g of a yellow oil are yielded.

2. Reduction of nitrosonaphthol

48 g of 1-nitroso-2-naphthol are suspended in a mixture of 300 ml ofwater and 60 ml of 5n NaOH, then another 240 ml of 5n NaOh are added.While stirring well hot water vapor is passed through the solution untilthe temperature reaches 35° C. Subsequently 120 g of freshly preparedsodium dithionite is added with the temperature rapidly rising to 60° C.The solution assumes an amber-colored tint. After 15 minutes, thesolution is rapidly cooled to under 20° C. by adding 200 g of ice and100 ml of concentrated hydrochloric acid. The white, flaky precipitationis filtered by vacuum and suspended in a mixture of 500 ml of water and50 ml concentrated hydrochloric acid. Overheated water vapor is passedinto this mixture with such a volume flow that the temperature reaches90° C. within 10 min. At this temperature is stirred another hour whilereducing the vapor flow. The still hot solution is filtered with theaubergine-colored precipitation remaining. Upon cooling the filtrate, alight, flaky precipitation falls out which is sucked away, scavengedwith diluted hydrochloric acid and then with ether and dried. Yieldedwere 45 g of 1-amino-2-naphthol-hydrochloride. The amino-hydroxyaromatic compounds were employed in all the transformations into thisacidic form, because the free bases with the exception of5-amino-6-quinoline proved to be very unstable.

3. Description of the oxazine compound

10 g (51 mmol) of 1-amino-2-naphthol-hydrochloride are boiled with 14 g(53 mmol) of diphenyl-bromacetaldehyde in 200 ml of toluol while addinga spatual tip of p-toluol sulfonic acid and stirring at the waterseparater. If no further reaction water is formed, the solution ispermitted to cool off. After extracting the solvent, the crude productis chromatographed with methylene chloride on aluminium oxide.

The fraction which runs red contains the photochromic compound whichshows an intensive red-violet photochromic tinting on the filter paperunder UV light. After extraction of the running medium, the productdiethyl ether/hexane is recrystallized. Yielded are 5.4 g of ared-tinged powder which was identified by means of NMR analysis as2,2-diphenyl-2H-naphth(2,1-b)oxazine (example 4).

Fabrication of Measuring Samples

For comparison, analog state of art compounds were synthetized for someof the compounds of table 1. These differ in structure by the exchangeof oxazine-nitrogen atoms for a CH residue are therefore pyrans whichare analog to oxazines.

Commercial zero lenses made of polydiethylene glycol bisallyl carbonate(diameter 71 mm, center thickness approximately 2 mm) are dyed on theirconvex side with the invented compounds as well as the referencesubstances using the process described in DE 35 16 568 A1.

Measurement Results

The produced lenses described in the preceding were measured in ameasuring bench according to DIN 58 217. The characteristic value is thespectral light-intensity sensitivity of the normal viewer. TheVλ-valuated difference between the transmission in the faded state τ_(o)and the excited state τ_(s) after 15 minute exposure to light at 23° C.in a tempered cell is in the ΔOD form the starting value:

    ΔOD=10 log τ.sub.o -10 log τ.sub.s.

After exposure to approximately 100 klux and a spectral distributionsimilar to the sun for 100 hours in the radiation test device (Suntest,Original Hanau), this difference is redetermined.

The quotient

    R=(ΔOD100 h ):(ΔOD 0 h)

is the remaining residual power. It relates to the starting value and isa direct reference radiation gage, because all the differences regardingspectral excitation and absorption, dying capability of the plasticmaterial, etc. have no influence. The results are shown in table 2.

                  TABLE 1                                                         ______________________________________                                        Substitution Scheme of the Invented                                           Photochromic Compounds                                                        Example                                                                              Base    R1      R2     R3     R4    R5                                 ______________________________________                                        1      A       H       H      H      H     H                                  2      A       H       H      H      H     OCH.sub.3                          3      A       H       2-CH.sub.3                                                                           H      H     H                                  4      B       H       H      H      H     H                                  5      B       H       H      H      H     OCH.sub.3                          6      B       H       2-CH.sub.3                                                                           H      H     H                                  7      B       H       H      OCOCH.sub.3                                                                          H     H                                  8      B       OCH.sub.3                                                                             2,3-benzo                                                                            H      H     H                                  9      C       H       H      H      H     H                                  10     C       H       H      H      C.sub.6 H.sub.5                                                                     H                                  11     D       H       H      H      H     H                                  12     E       H       H      H      H     H                                  ______________________________________                                    

The following shows the structural formula, where the resdiues listed intable 1 are located.

Base: ##STR1## 2 gives the lifetime of the individual compounds:

    ______________________________________                                         ##STR2##                                                                             X = N    X = CH (state of the art)                                    Comp. No. R (%)      Pat. No.    R (%)                                        ______________________________________                                        1         70         1' (US 3.567.605)                                                                         54                                           4         78         4' (US 3.627.690)                                                                         56                                           5         62         5' (WO 93/17071)                                                                          45                                           6         62         6' (WO 92/09593)                                                                          41                                           7         69         7' (US 5.066.818)                                                                         47                                           ______________________________________                                    

What is claimed is:
 1. A process for the production of photochromicoxazine compounds, characterized by an aldehyde bearing in theλ-position to the aldehyde group a halogen or hydroxy group (reactingagent 1) being condensed with a (substituted) ortho-amino-hydroxyaromatic compound (reacting agent 2).
 2. A process according to claim 1,characterized in that said reacting agent 1 is a (substituted)2-halogen- or 2-hydroxy-diphenyl-or phenyl-naphthyl-ordinaphthylacetaldehyde.
 3. A process according to claim 1, characterizedin that the aldehyde and the halogen or hydroxy group are located at acarbon atom which is part of a ring system.
 4. A process according toclaim 3, characterized in that said ring system is fluorene,dibenzosuberone, xanthene or thioxanthene.
 5. A process according toclaim 3, characterized in that said ring system is an aliphatic(monocyclic carbo or hetero cycle).
 6. A process according to claim 5,characterized in that said ring system is cyclohexane ortetrahydropyran.
 7. A process according to claim 3, characterized inthat said ring system is a polycyclic hydrocarbon such as adamantan,norbornane, norcamphor or fenchone.
 8. A process according to claim 1,characterized in that said reacting agent 2 is a (substituted)1-amino-2-naphthol or 2-amino-1-naphthol.
 9. A process according toclaim 1, characterized in that said reacting agent 2 is5-amino-6-hydroxyquinoline or 6-amino-5-hydroxyquinoline.
 10. A processaccording to claim 1, characterized in that said reacting agent 2 is5-amino-6-hydroxyisoquinoline or 6-amino-5-hydroxyisoquinoline.